:root {
    --primary-color: #1e293b;
    --secondary-color: #3b82f6;
    --accent-color: #ef4444;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-color: #334155;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
    --success-color: #10b981;
    --warning-color: #f59e0b;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
}

.hidden {
    display: none !important;
}

.page-header {
    background: linear-gradient(135deg, var(--primary-color), #0f172a);
    color: white;
    text-align: center;
    padding: 3rem 1.5rem 2.5rem;
    margin-bottom: 2rem;
}

.page-header h1 {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.page-header .subtitle {
    color: rgba(255, 255, 255, 0.7);
    font-size: 1rem;
    margin-bottom: 1rem;
}

.grade-badge {
    display: inline-block;
    background: var(--secondary-color);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 0 1.5rem 3rem;
}

.loading-state,
.error-state {
    text-align: center;
    padding: 3rem 1rem;
}

.loading-state i,
.error-state i {
    font-size: 2rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.error-state i {
    color: var(--accent-color);
}

.loading-state p,
.error-state p {
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.retry-btn {
    background: var(--secondary-color);
    color: white;
    border: none;
    padding: 0.6rem 1.5rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: opacity 0.2s;
}

.retry-btn:hover {
    opacity: 0.9;
}

.filter-bar {
    display: flex;
    align-items: flex-end;
    gap: 1rem;
    flex-wrap: wrap;
    background: var(--card-bg);
    padding: 1.25rem;
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
    margin-bottom: 1.5rem;
}

.filter-group {
    display: flex;
    flex-direction: column;
    gap: 0.3rem;
    flex: 1;
    min-width: 140px;
}

.filter-group label {
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.filter-group label i {
    margin-right: 0.25rem;
}

.filter-group select {
    padding: 0.55rem 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 0.9rem;
    color: var(--text-color);
    background: var(--bg-color);
    cursor: pointer;
    min-height: 44px;
}

.filter-group select:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.combo-wrap {
    position: relative;
}

.combo-input {
    width: 100%;
    padding: 0.55rem 0.75rem;
    padding-right: 2rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 0.9rem;
    color: var(--text-color);
    background: var(--bg-color);
    min-height: 44px;
    box-sizing: border-box;
}

.combo-input:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.combo-wrap::after {
    content: '\f078';
    font-family: 'Font Awesome 6 Free';
    font-weight: 900;
    position: absolute;
    right: 0.75rem;
    top: 50%;
    transform: translateY(-50%);
    font-size: 0.7rem;
    color: var(--text-muted);
    pointer-events: none;
}

.combo-list {
    display: none;
    position: absolute;
    top: calc(100% + 4px);
    left: 0;
    right: 0;
    max-height: 200px;
    overflow-y: auto;
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    z-index: 100;
    list-style: none;
    margin: 0;
    padding: 4px 0;
}

.combo-list.open { display: block; }

.combo-option {
    padding: 0.5rem 0.75rem;
    font-size: 0.85rem;
    color: var(--text-color);
    cursor: pointer;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.combo-option:hover,
.combo-option.active {
    background: #eff6ff;
    color: var(--secondary-color);
}

.combo-option.selected {
    font-weight: 600;
    color: var(--secondary-color);
}

.combo-option.all-option {
    font-weight: 500;
    color: var(--text-muted);
    border-bottom: 1px solid var(--border-color);
}

.combo-list::-webkit-scrollbar { width: 6px; }
.combo-list::-webkit-scrollbar-thumb { background: #cbd5e1; border-radius: 3px; }

.reset-btn {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    background: var(--bg-color);
    color: var(--text-muted);
    border: 1px solid var(--border-color);
    padding: 0.55rem 1rem;
    border-radius: 8px;
    font-size: 0.85rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s;
    min-height: 44px;
    white-space: nowrap;
}

.reset-btn:hover {
    background: var(--border-color);
    color: var(--text-color);
}

.overview-cards {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat-card {
    background: var(--card-bg);
    border-radius: 12px;
    padding: 1.25rem;
    text-align: center;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

.stat-icon {
    font-size: 1.2rem;
    color: var(--secondary-color);
    margin-bottom: 0.5rem;
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary-color);
    line-height: 1.2;
}

.stat-label {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-top: 0.25rem;
    font-weight: 500;
}

.table-container {
    background: var(--card-bg);
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table thead {
    background: var(--primary-color);
    color: white;
}

.data-table th {
    padding: 0.85rem 1rem;
    text-align: left;
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.data-table td {
    padding: 0.75rem 1rem;
    font-size: 0.9rem;
    border-bottom: 1px solid var(--border-color);
}

.data-table tbody tr:hover {
    background: rgba(59, 130, 246, 0.03);
}

.data-table tbody tr:last-child td {
    border-bottom: none;
}

.col-sn {
    width: 50px;
    text-align: center;
}

.col-roll {
    width: 80px;
    text-align: center;
}

.col-time {
    width: 100px;
    white-space: nowrap;
}

.status-completed {
    color: var(--success-color);
    font-weight: 600;
}

.status-incomplete {
    color: var(--warning-color);
    font-weight: 600;
}

.empty-state {
    text-align: center;
    padding: 3rem 1rem;
    color: var(--text-muted);
}

.empty-state i {
    font-size: 2rem;
    margin-bottom: 0.75rem;
    display: block;
}

.dashboard-footer {
    text-align: center;
    padding: 1.5rem 0 0;
    color: var(--text-muted);
    font-size: 0.8rem;
}

@media (max-width: 768px) {
    .page-header {
        padding: 3rem 1rem 2rem;
    }

    .page-header h1 {
        font-size: 1.5rem;
    }

    .overview-cards {
        grid-template-columns: repeat(2, 1fr);
    }

    .filter-bar {
        flex-direction: column;
        align-items: stretch;
    }

    .filter-group {
        min-width: 100%;
    }
}

@media (max-width: 480px) {
    .overview-cards {
        grid-template-columns: 1fr;
    }

    .table-container {
        overflow-x: auto;
    }

    .data-table {
        min-width: 550px;
    }

    .stat-value {
        font-size: 1.5rem;
    }
}